FIG. 1 depicts a prior art labelling device 100 for labelling moving objects. A label reel is placed in a holder 101 (label reel assembly), from where a web 102 is manually threaded through a printhead mechanism and finally onto the web take up assembly 106. The web is driven through the printhead mechanism 103 which houses a printing device that prints a label as it passes through the mechanism. Once printed the label is stripped off its backing web or carrier and fed onto a label pickup assembly 104. A linearly displaceable piston 105 is extended to take the label from the label pickup assembly, where the label may be rotated and finally held at a pre-set height above the item being labelled. Once the item is in position the label is blown onto the item.
The disadvantage with such a labelling device is that if the objects to be labelled have uneven surfaces, there is a risk that the labels will not attach to these uneven surfaces, and be blown away from the surfaces. These objects must then either be labelled manually or be recycled into the device in the hope that the next attempt to label the objects will succeed.
Moreover, if the height of the objects to be labelled is irregular and some of the objects have a height that is above the above mentioned pre-set height, the objects will be hit by the linearly displaceable piston, causing a blocking of the labelling device. In such cases, the piston typically moves slowly back to the starting position or an operator of the device must manually move the piston back to the starting position and restart the labelling device. Accordingly, this blocking does not only requrie extra manpower to monitor the device but also the impact from the piston on the object can easily damage the packing and even the object and delay the labelling operation.
The inventor of the present invention appreciated that there is thus a need for an improved labelling device that is capable of labelling objects with uneven surfaces and able to accommodate much greater height variations and has in consequence devised the present invention.